Wobbling device of sand belt grinder

ABSTRACT

In a wobbling device of a sand belt grinder of the invention, a set of electromagnetic movable members is disposed outside a sand belt shaft base, and micro switches are disposed under two sides of the sand belt shaft base so that the control of continuously powering on and off is generated and the electromagnetic movable members generate continuously attracting and releasing operations. In addition, the movable members drive the shaft base and a sand belt to generate reciprocated wobbling operations at specific angles. Thus, when the sand belt is grinding, the sand belt generates the leftward and rightward sliding movement in a larger area so that the excellent polishing effect and the economic effectiveness can be obtained.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The invention relates to a device, in which electromagnetic movable members and micro switches are properly applied to a sand belt grinder. Under the control of the attracting and releasing operations generated by the electromagnetic movable members, the movable members drive a sand belt shaft base and a sand belt to generate reciprocated wobbling operations so that the best grinding effectiveness can be generated between the ground wood material and the sand belt.

(2) Description of the Prior Art

Sand belt grinders are widely used in various surface grinding and polishing machines for wood materials and have the very important influences on the machining operation of the wood materials. That is, the quality of grinding the wood material directly relates to the quality of the fracture. In the conventional sand belt grinder, a ring-shaped sand belt is wound around two grinding shafts, which are rotated to drive the sand belt to circle round and round and to roughly and finely grind or polish the surface of the wood material moving across the lower portion of the grinder. The process is quick and convenient so that the mass production can be achieved. Thus, the sand belt grinder is very advantageous to the industry of wood material machining.

In practice, however, the grinding operation of the sand belt still has the following drawbacks.

First, the sand belt is wound around the upper and lower rotating shafts, so its moving track is fixed and the wood chips tend to be accumulated on the surface of the sand belt. If the grinder is not timely stopped and the wood chips are not timely cleaned, the accumulated wood chips tend to cause the insufficiently ground phenomenon on the surface of the wood material, or to cause the scratched phenomenon because the larger particles of the wood chips are generated. Thus, the grinding quality cannot be easily controlled.

Second, because the wood chips tend to be accumulated on the surface of the sand belt, the heat dissipating effect on the surface of the sand belt is poor, the burn marks on the surface of the material tend to be formed, and the lifetime of the sand belt may be challenged. If the sand belt is replaced too frequently, the throughput is influenced and the consumed sand belts also increase the loading of the manufacturer.

The conventional grinder still has to be improved in the industry of wood machining because the sand belt performs the grinding along the fixed path, the disadvantageous influences on the material grinding quality and the throughput tend to be caused, the grinder has to be stopped for cleaning and the sand belt has to be replaced frequently.

SUMMARY OF THE INVENTION

In view of the drawbacks caused by the sand belt grinder with the wound sand belt, the present inventor has paid attention to the research and development according to the experience and the technology, and thus developed this wobbling device of this invention. The main object of the invention is to make a sand belt shaft base have a properly movable state, and a set of electromagnetic movable members in conjunction with micro switches are provided to perform the control. Thus, continuously attracting and releasing operations generated by the electromagnetic movable members drive the sand belt shaft base to generate the reciprocated wobbling operations so that the sand belt wound therearound generates the grinding path variation, and the finer grinding and polishing effects on the material surface may be obtained.

Another object of the invention is to drive the sand belt to synchronously wobble in a larger area of grinding path according to the back and forth wobbling of the sand belt shaft base so that the maximum usage range of the same sand belt can be obtained.

Still another object of the invention is to improve the condition that the wood chips are accumulated on the surface of the sand belt so that the scratch phenomenon generated on the surface of the material may be minimized.

Yet still another object of the invention is to prevent the grinder from being stopped for cleaning frequently and to lengthen the lifetime of the sand belt because the wood chips accumulated on the surface of the sand belt can be greatly reduced.

Further aspects, objects, and desirable features of the invention will be better understood from the detailed description and drawings that follow in which various embodiments of the disclosed invention are illustrated by way of examples.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a pictorially assembled view showing an upper body of a sand belt grinder according to the invention.

FIG. 2A is a partially assembled view showing a wobbling member of the sand belt grinder of the invention.

FIG. 3 is a partially pictorially assembled view showing the wobbling member of the sand belt grinder of the invention.

FIG. 4 is a schematic illustration showing the arrangement of micro switches disposed under a sand belt shaft base of the sand belt grinder of the invention.

FIG. 5 is a schematic illustration showing associated positions of the sand belt shaft base and two micro switches of the sand belt of the invention.

FIG. 6 is a schematic illustration showing associated positions of the members when the sand belt shaft base wobbles toward one side.

FIG. 7 is a schematic illustration showing associated positions of the members when the sand belt shaft base wobbles toward the other side.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The structure, combination, technological means and effect of invention will be described in detail with reference to the accompanying drawings.

Referring first to FIG. 1, an upper seat 10 of a sand belt grinder of the invention mainly includes an upper base 11, a material feeding platform 12, and a left bracket 21 and a right bracket 20 respectively disposed on left and right sides. Upper and lower sand belt shaft bases 30 are disposed between the left and right brackets, and a ring-shaped sand belt (not shown) is wound around sand belt shafts 33 of the sand belt shaft base 30. Thus, the grinder can perform the predetermined grinding or polishing operation on the material moving past the material feeding platform 12.

In order to make the sand belt shafts 33 on the sand belt shaft base 30 generate the proper wobbling operation to improve the sand belt grinding operation and to enhance the effectiveness, a set of fixing frames 40 is particularly disposed inside the right bracket 20. As shown in FIGS. 1 to 3, the fixing frame 40 has a positioning plate 41 disposed above the bracket, and an electronic magnet 42 and a support plate 44 corresponding to each other are disposed on the positioning plate 41. A return spring 45 is disposed between a magnetic slider 43, disposed in the electronic magnet 42, and the support plate 44. According to the spring 45, the magnetic slider 43, which is attracted inside when the electronic magnet 42 is powered on, can be pulled back by the spring 45 at the moment when the electronic magnet 42 is powered off. Thus, the continuous on and off operations of the electronic magnet 42 enable the magnetic slider 43 to generate the continuously reciprocating sliding movement.

According to the reciprocating sliding movement of the magnetic slider 43, a combination hole 46 is further formed on the front end of the magnetic slider 43 to align with a through hole formed on the front edge of a connection plate 32 disposed outside a shaft base side plate 31 so that a combination rod 47 may be inserted into the through hole and the combination hole 46 to connect the connection plate 32 to the magnetic slider 43. Thus, when the magnetic slider 43 generates the reciprocating sliding movement, the connection plate 32, the sand belt shaft base 30, the sand belt shaft 33 and the sand belt (not shown) may be driven to wobble back and forth so that the sand belt can perform the large area grinding and polishing operations along the floating track to grind and polish the material moving past the material feeding platform 12, and the high-quality sand belt grinding operation can be generated.

In order to make the sand belt shaft base 30 generate the operations similar to the back and forth wobbling operations, the control of continuously powering on and off the electronic magnet 42 can be performed. As shown in FIGS. 3 and 4, a set of corresponding micro switches 35 and 36 is disposed on two sides below a base plate 34 of the sand belt shaft base so that the intermittently powering on and off operations can be generated to ensure that the reciprocating operations of the magnetic slider 43 can be continuously performed.

The intermittently powering on and off operations generated by the micro switches 35 and 36 will be described in detail with reference to FIGS. 5 to 7. FIG. 5 shows the state where a sand belt 50 is located at the middle position before the sand belt shaft base 30 operates. At this time, the sand belt 50 is not in contact with any one of the micro switches 35 and 36. When the sand belt grinder starts and the electronic magnet 42 is powered on such that the magnetic slider 43 is attracted inside, the sand belt shaft base 30 enters the slantingly wobbling state, as shown in FIG. 6. Meanwhile, the sand belt 50 is biased leftwards and in contact with an actuating sheet 37 of the micro switch 35, and the actuating sheet 37 is pressed inside to make the micro switch 35 power off the electronic magnet 42. When the electronic magnet 42 is powered off, as mentioned hereinabove and its magnetic slider 43 is pulled by the return spring 45 so that the sand belt shaft base 30 generates the other-side wobbling, as shown in FIG. 7, the sand belt 50 immediately slides to an exposed actuating sheet 38 above the micro switch 36 to press it down to trigger the micro switch 36 to enter a turn-on state, and the other side wobbling state shown in FIG. 6 is returned. Thus, the operations are repeated so that the sand belt shaft base 30 and the sand belt 50 generate the continuously reciprocated wobbling operations, and the sand belt 50 generates the enlarged grinding path for the material in the reciprocating operations. Thus, the economic effectiveness of enhancing the grinding quality, reducing the wood chips accumulated on the sand belt, and lengthening the lifetime can be obtained.

Consequently, the electronic magnets and the micro switches are properly arranged in this invention so that the sand belt grinder has the novel grinding effect and may be widely applied to the material grinding industry. Thus, the machining quality and the economic effectiveness can be enhanced.

New characteristics and advantages of the invention covered by this document have been set forth in the foregoing description. It is to be expressly understood, however, that the drawings are for the purpose of illustration only and are not intended as a definition of the limits of the invention. Changes in methods, shapes, structures or devices may be made in details without exceeding the scope of the invention by those who are skilled in the art. The scope of the invention is, of course, defined in the language in which the appended claims are expressed. 

1. A wobbling device of a sand belt grinder, mainly characterized in that a fixing frame is disposed between brackets of an upper base of the grinder and a sand belt shaft base, and a set of electronic magnets is disposed on the fixing frame so that magnetic sliders disposed therein generate reciprocating motion in intermittently attracting and releasing operations of the electronic magnets so that the sand belt shaft base and a sand belt generate synchronous back and forth wobbling operations.
 2. The wobbling device of the sand belt grinder according to claim 1, wherein the magnetic sliders of the electronic magnets generate return operations by return springs after power is off.
 3. The wobbling device of the sand belt grinder according to claim 1, wherein the magnetic sliders of the electronic magnets are connected to the sand belt shaft base to generate synchronously wobbling operations.
 4. The wobbling device of the sand belt grinder according to claim 1, wherein the electronic magnets generate the intermittently attracting and releasing operations using two corresponding micro switches.
 5. The wobbling device of the sand belt grinder according to claim 4, wherein actuating sheets are disposed on the micro switches and are pressed by the sand belt shifting leftwards and rightwards to control intermittent operations of powering on and off the micro switches. 